This invention relates to deposition of inorganic oriented crystal layers using ion beam deposition technology.
Crystallites having the same orientation with respect to the plane of the substrate but twisted relative to each other have been produced. While this property is useful for catalysis, hardness or corrosion properties, materials having this property are not useful as seed layers for electronic materials. Electronic materials must be as defect free as possible, and they need to be single crystals or single crystal-like to achieve optimum electrical performance. These materials have been produced using molecular beam epitaxy, which requires the use of a single crystal surface on which to grow the electronic material and multiple sources. Therefore, there is a need for simpler, faster methods of production that can build oriented crystal layers on substrates other than single-crystal substrates, particularly for uses such as high temperature material applications.
It is an object of this invention to provide an apparatus and method for deposition of oriented crystal layers on substrate materials.
It is another object of this invention to provide an apparatus and method for producing a single crystal like substrate on inexpensive amorphous materials such as glass.
It is a further object of this invention to provide an apparatus and method for deposition of oriented crystal layers on substrate materials in high vacuum rather than ultrahigh vacuum environments.
It is yet another object of this invention to provide an apparatus and method for producing single crystal like substrates that will allow the growth of high quality oriented crystal materials.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. The claims are intended to cover all changes and modifications within the spirit and scope thereof.
To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, thin films of oriented crystals have been made by using flow through ion beam deposition during specific substrate rotation about an axis in a clocking action. The substrate is quickly rotated to a selected deposition position, paused in the deposition position for ionized material to be deposited, then quickly rotated to the next selected deposition position.
The clocking motion can be achieved by use of a lobed cam on the spindle with which the substrate is rotated or by stopping and starting a stepper motor at long and short intervals. The deposition positions are selected in accordance with the orientation and structure of the crystals to be deposited on the substrate. For example, the substrate is rotated from 12 to 3 to 6 to 9 and back to 12 during deposition for four-fold symmetry type crystals. Other symmetries can be programmed into the process, allowing virtually any oriented inorganic crystal to be grown on the substrate surface.